Delivery of tailor-made cobalamin to methylmalonyl-CoA mutase

Methylmalonyl coenzyme A mutase (MCM) catalyzes the adenosylcobalamin-dependent isomerization of methylmalonyl-CoA to succinyl-CoA. Adenosyltransferase, an enzyme that carries out the final step in biosynthesis of adenosylcobalamin, is shown to be involved in delivery of the cofactor to MCM.